Heat the 2 tablespoons of EVOO in a large pot or Dutch oven over medium heat. Once the oil is shimmering, add the chopped red onion and mushrooms. Cook for 5-7 minutes, stirring occasionally, until the onions are soft and translucent, and the mushrooms are golden brown.
Push the sautéed vegetables to the side of the pot and add the ground beef. Break the meat up with a spatula and cook until browned, about 5-7 minutes. Drain any excess fat from the pot, if necessary.
Sprinkle the garlic powder, chili powders, tajin and kosher salt over the beef and vegetables. Stir well to combine. Next, pour in the crushed tomatoes, tomato sauce, and diced tomatoes. Stir everything together, making sure the tomatoes are evenly distributed.
Drain and rinse the pinto, kidney, and black beans. Add the beans to the pot, along with the 1 1/2 cups of water. Stir to combine all the ingredients, then bring the chili to a simmer.
Reduce the heat to low, cover the pot, and let the chili simmer for about 20-30 minutes, stirring occasionally to prevent sticking. This will allow all the flavors to meld together beautifully. Taste and adjust seasoning, if needed.
Once the chili is done, serve it hot with your favorite toppings! Some great options include shredded cheese, sour cream, chopped cilantro, or a squeeze of lime.